chrome/test/data/extensions/api_test/file_system/retain_directory/manifest.json

{
  "name": "chrome.fileSystem.retainEntry test",
  "manifest_version": 2,
  "version": "0.1",
  "description": "Test for chrome.fileSystem.retainEntry",
  "app": {
    "background": {
      "scripts": ["background.js"]
    }
  },
  "permissions": [{"fileSystem": ["directory"]}]
}